As part of a deployment of fiber to the premises (FTTP) networking to individual customer premises (for example, residential homes), an “optical network terminal” unit (ONT) needs to be installed at each customer premises. The ONT provides the interface between the customer premises communications equipment (telephone, data, video STB and TVs) and the fiber network. Current ONTs, particularly those used with FTTP networks that are passive optical networks (PONs), require their own power supplies, as the fiber network does not supply power to the customer premises. Current implementations of the ONT may include a power connection to standard customer premises power supply (e.g., 110 VAC) via a cable configured to be usable with standard power outlets.
One concern raised by ONTs is that a power outage at the customer premises may prevent access to telephone communications over the fiber network via the ONT. In order to address these concerns, current ONT implementations specify the use of a uninterruptible power supply (UPS)—such as a backup battery—to power the ONT, such that the UPS provides power to the ONT upon power failure. The current specification for ONT UPSs requires that the UPS provide enough power to allow the ONT to provide up to eight hours of telephone services to the customer. The UPS is typically deployed with the ONT, such that the ONT draws its power from the UPS or from the customer premises power supply. The UPS is typically deployed separately from the ONT, allowing it to be independently maintained and placed in environmentally friendly locations (e.g., in the interior of the customer premises). This requires power supply cabling between the ONT and the UPS.
Power supply cabling is governed by both physical laws (e.g., Ohm's law) and legal regulations. For example, the cabling between the ONT and the customer premises power outlet is typically eight feet in length or shorter in order to comply with electrical and building codes. The cabling between the UPS and the ONT is ideally less than 50 feet in length in order to reduce resistive losses. Additionally, the location of the customer premises power source (e.g., a power outlet) must comply with applicable building codes regarding power wiring, which may limit outlet placement. With these restrictions, the installation costs associated with installing an ONT can be significant, as additional electrical installations may be required to accommodate the ONT.
Investigating various building constructions and home layouts, it was determined that at least 10% of a sampling of homes would not have a power outlet within the placement constraints of existing power supply cabling. In those cases, an electrical contractor would need to be dispatched and required to install an electrical outlet in an area that was acceptable to the customer and within the design constraints of the UPS/ONT, at a significant expense and delay.